[Ocfs2-devel] + sysctl-use-rcu-protected-sysctl-for-ocfs-group-add-helper.patch added to -mm tree

[Andi Kleen <andi@firstfloor.org>]

> Accesses would be:
>         char *str; 
> 	rcu_read_lock();
>         str = rcu_deref(NAME.str);
>         ....
> 	rcu_read_unlock();
> 
> Updates would be:
>         char *next;
> 	mutex_lock(&rcu_string_mutex);
>         next = rcu_string->data;
>         if (next == rcu_string->str)
>         	next = rcu_string->data + rcu_string->size;
>         memcpy(next, somestring_from_somewhere, rcu_string->size);
>         next[rcu_string->size - 1] = '\0';
>         rcu_string->str = next;
>         synchronize_rcu();
>         mutex_unlock(&rcu_string_mutex);

synchronize_rcu inside a lock is a bit nasty, but ok none of these
are critical.

> 
> Thoughts?

It's not fully clear to me how this is better than my solution?

-Andi
-- 
ak at linux.intel.com -- Speaking for myself only.